With the development of display technology, the flat panel device, such as Liquid Crystal Display (LCD) possesses advantages of high image quality, power saving, thin body and wide application scope. Thus, it has been widely applied in various consumer electrical products, such as mobile phone, television, personal digital assistant, digital camera, notebook, laptop, and becomes the major display device.
Touch panel provides a new human machine interactive interface. The usage is more direct and with more humanization. Forming a touch control device with combining the touch panel and the flat display device is capable of providing the touch control function to the flat display device. With the fingers, the stylus for inputting, the operation can be more intuitive and easy.
The touch control display panels can be categorized into four types of resistive, capacitive, optics, surface acoustic wave types according to sensing technology. At present, the main stream touch control technology is the capacitive type. The capacitive type can be further categorized into self capacitive type and mutual capacitive type. The main capacitive type touch control display panel in the present market is the mutual capacitive type, and the advantage of the mutual capacitive type is being able to achieve multi-touch control. According to the difference of the structures, the touch control display panels can be categorized: the touch control circuit covering on cell (On Cell), the touch control circuit embedded in cell (In Cell) and Out Cell. The In Cell type possesses advantages of low cost, being ultra thin and narrow frame, which is mainly applied in the high end touch control product. However, the process difficulty of the In Cell type touch control technology is higher, and the factor of signal interference exists, and the sensitivity is worse. The Out Cell type is applied for most of the touch control display panels in the present market. The advantages of the Out Cell type are high sensitivity and fast response speed. The drawbacks are high cost and restriction for the ultra-thin product. The On cell type integrates the advantages of the Out Cell type and the In Cell type, and can promote the sensitivity and decrease the panel thickness, too.
In prior art, the On cell type touch control display panel generally comprises: a first Indium Tin Oxides (ITO) layer, an insulation layer covering on the ITO layer and a bridging layer located on the insulation layer. The first ITO layer is formed with a plurality of driving electrodes and a plurality of sensing electrodes. The plurality of the sensing electrodes are connected by the ITO connecting lines in the same layer, and the plurality of driving electrodes are connected by the bridging lines in the bridging layer through the vias of the insulation layer. In the touch control display of such structure, the insulation layer completely covers on the first ITO layer except the via area. As being touched, the total capacitance change is smaller, which results in the low signal to noise of the touch control display panel, and the touch result is poor.